This invention relates to an air bearing and motor cooling arrangement.
Electric motors have several significant sources of heat that must be cooled to ensure desired operation of the motor. One significant source of heat is generated by the stator producing a magnetic field to drive a rotor assembly. Another significant source of heat is generated by bearings used to support the rotor assembly. In some high temperature motor applications, air bearings are used.
The air bearings and stator of an electric motor have been cooled using two airflow paths that are separate from one another. That is, the airflow paths have separate inlets and separate outlets. As a result of using separate flow paths, the bearings are subject to different loads based upon the different pressures in the flow paths that are exerted on the rotor assembly, bearings, and seals. The imbalance of load on the bearings increases the load on a thrust bearing used to support the rotor assembly, which is undesirable.
Cooling the air is typically provided from a pressurized air source, which reduces the efficiency of the component providing the pressurized air. Further, in the event of a failure of that component, flow of cooling air to the electric motor will cease possibly resulting in a failure of the electric motor.
What is needed is improved cooling flow paths and a more efficient manner in which to provide the electric motor with cooling air.